Shenzhen Zhongnuo Testing Technology Co., Ltd. specializes in the calibration, verification, and metrological services for equipment such as gas detectors, flammable gas detectors, and harmful gas detectors for various locations. We provide certification services nationwide, addressing all sorts of electrical safety and explosion-proof fire prevention issues for clients, and contributing to safe production.
Gas Alarm Detector Regular Inspection Content
Installation spacing of inspection (testing) points
2. Installation Height of the Detector
3. Indication Error (Concentration)
4. Repeatability (Concentration)
5. Alarm Error (Concentration)
6. Response Time (Seconds)

Verification Method
Appearance and structure
Inspect and feel according to requirements of Section 4.1
Logos and Branding
Inspect in accordance with the requirements of Section 4.2.
Power-on Inspection
Inspect visually and by touch, in accordance with the requirements of 4.3, to check the 5.3.4 alarm function and alarm action values.
Introduce a standard gas substance with a concentration exceeding the alarm set point, causing the instrument to trigger an alarm. Observe whether the instrument's audio-visual alarm functions normally and record the instrument's reading at the time of alarm. Repeat the measurement three times; the arithmetic mean of the three readings is the instrument's alarm trigger value.

Key Technical Requirements for Regular Calibration of Combustible Gas Detectors (Shenzhen ZhongNuo Testing Technology Co., Ltd.)
1. Power-On Self-Check Function: The instrument should have an automatic self-check function upon startup, with a manual self-check function for alarm components as well.
2. Specify the effective detection distance: The effective detection distance of the non-contact gas alarm instrument shall not be less than 20 m.
3. Alarm Value Setting: Specific alarm value settings are stipulated by the standard for different gases.
For example, the oxygen deficiency alarm setpoint is 19.5%VOL, and the high oxygen alarm setpoint is 23.5%VOL (refer to GB 8958—2006 "Operation Procedures for Oxygen Deficiency Hazardous Work" and GB 30871—2022 "Special Operations Regulations for Hazardous Chemical Enterprises").
The first-level combustible gas alarm setpoint is not greater than 25% LEL, and the second-level alarm setpoint is not greater than 50% LEL.
The first and second-level alarm settings for toxic and harmful gases are determined based on OEL (Occupational Exposure Limit) or IDLH (Immediate Danger to Life and Health).
4. Error and Repetition: The standard specifies clear requirements for the indicating error, drift, and repeatability of the instrument. For instance, the indicating error for flammable gases, toxic and harmful gases, and oxygen should be no more than 5% FS, 5% FS, and 2% FS respectively within the normal test range of the instrument's full scale.
5. Calibration and Interfaces: The instrument should be easy to calibrate, with set calibration procedures and corresponding interfaces to ensure the accuracy of its measurement results.
6. Explosion-proof Performance: Equipment used in explosive environments must have explosion-proof performance in compliance with relevant regulations and obtain an explosion-proof certificate.
7. Audio-Visual Alarm Device: The audio-visual alarm device of the alarm should meet the visibility and sound pressure level requirements under specific conditions, ensuring effective alerting of staff during emergencies.
8. Output Control Function: Instruments with output control capabilities should be able to activate the output control function upon emitting an alarm signal, such as cutting off power supply or initiating the exhaust system, etc.
9. Power Requirements: Specific requirements are outlined for power supply voltage, continuous operating time, etc., for both battery-powered and non-battery-powered instruments.
10. Other Performance Requirements: Including specifications for bearing, response time, full-scale indication error, high-speed airflow, long-term stability, insulation withstand voltage, temperature, constant humidity and heat, electromagnetic interference resistance, steam interference resistance, vibration and drop, and functionality.

What does a calibration report for a flammable gas detector typically include?
The verification results should be reflected on the verification certificate or report, and the verification proof or report must include the following information.
① Title, such as "Calibration Certificate" or "Calibration Report";
② Laboratory Name and Address
③ Calibration Location (if not calibrated in the laboratory)
④ Standing proof or report (e.g., with serial number), indicating each page and page number;
5. Provide the sender's name and address.
⑥ Describe the target school clearly and explicitly.
Calibration date and receipt date;
⑧ Technical specifications for calibration base, including name and code;
⑨ Description of traceability and validity of the measurement standards used for calibration;
⑩ Description of Calibration Environment
11. Calibration Results and Measurement Uncertainty Statement
12. Signature, title, or equivalent symbol of the issuer of the calibration certificate or report; and issuance date
13. Calibration results are only applicable to the calibration object.
14. No part of the certificate or report may be copied without written approval from the laboratory.
Re-review interval
Instrument recalibration is typically every 1 year, determined by the submitting unit based on actual usage. During the secondary calibration process, if there are doubts about the instrument's test data, or if the main components of the instrument are replaced, or if recalibration is needed after repairs.
Shenzhen Zhongnuo Testing Technology Co., Ltd. is a third-party institution specializing in electrical safety, electrical explosion-proofing, gas alarm systems, and toxic/hazardous gas detection instruments for regular inspections, metrological measurements, and calibration services. We are qualified to address fire and explosion prevention issues for our clients.